/*
 * FreeRTOS V202212.00
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

/* Standard includes. */
#include <stdint.h>
#include <stdio.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"

/* FreeRTOS+CLI includes. */
#include "FreeRTOS_CLI.h"

/* FreeRTOS+UDP includes. */
#include "FreeRTOS_UDP_IP.h"
#include "FreeRTOS_Sockets.h"

/* Demo app includes. */
#include "UDPCommandInterpreter.h"

/* Dimensions the buffer into which input characters are placed. */
#define cmdMAX_INPUT_SIZE              60

/* Dimensions the buffer into which string outputs can be placed. */
#define cmdMAX_OUTPUT_SIZE             1250

/* Dimensions the buffer passed to the recvfrom() call. */
#define cmdSOCKET_INPUT_BUFFER_SIZE    60

/*
 * The task that runs FreeRTOS+CLI.
 */
void vUDPCommandInterpreterTask( void * pvParameters );

/*
 * Open and configure the UDP socket.
 */
static xSocket_t prvOpenUDPServerSocket( uint16_t usPort );

/*-----------------------------------------------------------*/

void vStartUDPCommandInterpreterTask( uint16_t usStackSize,
                                      uint32_t ulPort,
                                      UBaseType_t uxPriority )
{
    xTaskCreate( vUDPCommandInterpreterTask, "CLI", usStackSize, ( void * ) ulPort, uxPriority, NULL );
}
/*-----------------------------------------------------------*/

/*
 * Task that provides the input and output for the FreeRTOS+CLI command
 * interpreter.  In this case a UDP port is used.  See the URL in the comments
 * within main.c for the location of the online documentation.
 */
void vUDPCommandInterpreterTask( void * pvParameters )
{
    long lBytes, lByte;
    signed char cInChar, cInputIndex = 0;
    static char cInputString[ cmdMAX_INPUT_SIZE ], cOutputString[ cmdMAX_OUTPUT_SIZE ], cLocalBuffer[ cmdSOCKET_INPUT_BUFFER_SIZE ];
    BaseType_t xMoreDataToFollow;
    struct freertos_sockaddr xClient;
    socklen_t xClientAddressLength = 0; /* This is required as a parameter to maintain the sendto() Berkeley sockets API - but it is not actually used so can take any value. */
    xSocket_t xSocket;

    /* Just to prevent compiler warnings. */
    ( void ) pvParameters;

    /* Attempt to open the socket.  The port number is passed in the task
     * parameter.  The strange casting is to remove compiler warnings on 32-bit
     * machines. */
    xSocket = prvOpenUDPServerSocket( ( uint16_t ) ( ( uint32_t ) pvParameters ) & 0xffffUL );

    if( xSocket != FREERTOS_INVALID_SOCKET )
    {
        for( ; ; )
        {
            /* Wait for incoming data on the opened socket. */
            lBytes = FreeRTOS_recvfrom( xSocket, ( void * ) cLocalBuffer, sizeof( cLocalBuffer ), 0, &xClient, &xClientAddressLength );

            if( lBytes != FREERTOS_SOCKET_ERROR )
            {
                /* Process each received byte in turn. */
                lByte = 0;

                while( lByte < lBytes )
                {
                    /* The next character in the input buffer. */
                    cInChar = cLocalBuffer[ lByte ];
                    lByte++;

                    /* Newline characters are taken as the end of the command
                     * string. */
                    if( cInChar == '\n' )
                    {
                        /* Process the input string received prior to the
                         * newline. */
                        do
                        {
                            /* Pass the string to FreeRTOS+CLI. */
                            xMoreDataToFollow = FreeRTOS_CLIProcessCommand( cInputString, cOutputString, cmdMAX_OUTPUT_SIZE );

                            /* Send the output generated by the command's
                             * implementation. */
                            FreeRTOS_sendto( xSocket, cOutputString, strlen( cOutputString ), 0, &xClient, xClientAddressLength );
                        } while( xMoreDataToFollow != pdFALSE ); /* Until the command does not generate any more output. */

                        /* All the strings generated by the command processing
                         * have been sent.  Clear the input string ready to receive
                         * the next command. */
                        cInputIndex = 0;
                        memset( cInputString, 0x00, cmdMAX_INPUT_SIZE );

                        /* Transmit a spacer, just to make the command console
                         * easier to read. */
                        FreeRTOS_sendto( xSocket, "\r\n", strlen( "\r\n" ), 0, &xClient, xClientAddressLength );
                    }
                    else
                    {
                        if( cInChar == '\r' )
                        {
                            /* Ignore the character.  Newlines are used to
                             * detect the end of the input string. */
                        }
                        else if( cInChar == '\b' )
                        {
                            /* Backspace was pressed.  Erase the last character
                             * in the string - if any. */
                            if( cInputIndex > 0 )
                            {
                                cInputIndex--;
                                cInputString[ cInputIndex ] = '\0';
                            }
                        }
                        else
                        {
                            /* A character was entered.  Add it to the string
                             * entered so far.  When a \n is entered the complete
                             * string will be passed to the command interpreter. */
                            if( cInputIndex < cmdMAX_INPUT_SIZE )
                            {
                                cInputString[ cInputIndex ] = cInChar;
                                cInputIndex++;
                            }
                        }
                    }
                }
            }
        }
    }
    else
    {
        /* The socket could not be opened. */
        vTaskDelete( NULL );
    }
}
/*-----------------------------------------------------------*/

static xSocket_t prvOpenUDPServerSocket( uint16_t usPort )
{
    struct freertos_sockaddr xServer;
    xSocket_t xSocket = FREERTOS_INVALID_SOCKET;

    xSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );

    if( xSocket != FREERTOS_INVALID_SOCKET )
    {
        /* Zero out the server structure. */
        memset( ( void * ) &xServer, 0x00, sizeof( xServer ) );

        /* Set family and port. */
        xServer.sin_port = FreeRTOS_htons( usPort );
        xServer.sin_family = FREERTOS_AF_INET;

        /* Bind the address to the socket. */
        if( FreeRTOS_bind( xSocket, &xServer, sizeof( xServer ) ) == -1 )
        {
            FreeRTOS_closesocket( xSocket );
            xSocket = FREERTOS_INVALID_SOCKET;
        }
    }

    return xSocket;
}